The parafacial or parafacialia is the area between ptilinal fissure and the compound eye of dipterans. [1]
In anatomy, a fissure is a groove, natural division, deep furrow, elongated cleft, or tear in various parts of the body also generally called a sulcus, or in the brain a sulcus.
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distinguish brightness and color. The image perceived by the arthropod is a combination of inputs from the numerous ommatidia, which are oriented to point in slightly different directions. Compared with single-aperture eyes, compound eyes have poor image resolution; however, they possess a very large view angle and the ability to detect fast movement and, in some cases, the polarization of light.
